Disk Drill is a free Mac data recovery software designed natively for Mac OS: easily protect your files from accidental deletion with Recovery Vault and recover lost data from Mac disks. When something is deleted Recovery Vault makes it possible to recover not only the file itself, but also its properties, such as original file name, location, etc.

Disk Drill also includes powerful S.M.A.R.T. disk monitoring right out-of-the-box; you can monitor your disks' hardware status and get automatic notifications of potential failures or other issues. If a disk or partition is failing, you can easily backup it into a disk image (DMG) which can later be mounted for recovery.

Disk Drill PRO also features a number of advanced scanning modes for data recovery of FAT, NTFS, HFS/HFS+, other file systems.Using Quick Scan you can locate deleted items on FAT and NTFS disks, this scanning method is fast and accurate, but is unlikely to find data deleted long ago. With Deep Scan you can try to recover data from any disk or memory card regardless of their file system. This recovery method is long and thorough, it scans your disk in a binary mode and is capable of finding deleted files even after formatting.

Although the "Pro" version is a little pricy, it is worth it. I had an NTFS volume that I could NOT recover files from under Windows with a Windows app (Advanced NTFS Undelete). Disk Drill Pro could and did.

This software rules! It took quite long to "deep scan" a 1 TB raid 0 broken disk, but it popped out a vast majority of the files I assumed I had lost forever. And the same is doing for the other volume. Impressive! The customer care is fast and the developers are very active. This program (I use the one on app store, but those are quite the same) is a little jewel. If you ever will have the sadness to face a RAID 0 brokedown, consider this app for a spin.

Disk Drill for me is simply hands down the best recovery software for Mac.
I share my laptop with my 2 kids, a disaster waiting to happen. I used Disk Drill when it was in beta and it has saved me at least half a dozen times.
It is so simple to use and doesn't hog resources. Several of my friends have installed Disk Drill and a couple have upgraded to the Pro version, the main reason being that there is no huge learning curve and the software works. Put Disk Drill on your 'must have software' list Better still just download it now, you won't look back . . well if you do your lost files will be waiting for you.

It does happen - your iMac becomes slower and slower, than can not see you hard drive. Bummer - take your drive out, install the new HD and reinstall your OSX from media. Install you "dead" HD in external disk enclosure, hook up to your iMac via USB, FireWire most likely want work - your iMac knows that this HD serial number is considered "dead".
How about all your zillions of music, video and pictures. These are on your external drive now. How to recover them?
Answer is Disk-Drill. It found all of my Audio, Pictures and Video files, some films are GBytes size.
I was more than impressed, Disk Drill actually works and it is free.

Before I discovered Disk Drill I try commercial disk recovery software, evaluated "Demo" programs and bought one for more than $100. Well, >$100 later found that it can not recover files larger than 30MB, could not find directories names nor file names. Called "support", yes "support' because there was no support. Calls and e_mails just waist of time.